There's another milestone today in the long effort to eliminate Syria's chemical weapons. The international overseeing the effort is unveiling more details of its plan and this is all a bit complicated. The first stage could be the hardest - moving the chemicals overland in the middle of a civil war to a Syrian port.

NPR Pentagon correspondent Tom Bowman has been reporting on the story and he joins us to help us understand how this plan is going to work. Tom, good morning.

TOM BOWMAN, BYLINE: Good morning, David.

GREENE: So this report being released today, how are they going to pull this off?

BOWMAN: Well, David, it's basically a four step process. First, you move 500 tons of chemical agents - it's mustard agent - and then the components to make nerve agents in trucks across Syria to the port of Latakia. And then they're loaded on ships provided by Norway and Denmark. The ships in turn are expected to head to a port in Italy, and that's where the chemicals will be transferred to a U.S. government ship, called the Cape Ray. And then the Cape Ray will head out to sea and neutralize the chemicals with specialized equipment.

GREENE: I heard you mention Norway, Denmark, the United States, Italy. I mean there are a lot of countries involved here, which has to make things even more complex.

BOWMAN: It is. And, you know, a lot of other countries were negotiating whether they would accept the chemicals into their ports or their territory. They refused. It took weeks and weeks of planning to do this. Very sensitive negotiations, you might imagine, since we're talking about chemical weapons and arsenals. So it took a lot of weeks to come up with this plan and they finally have - have it all set.

GREENE: OK. So the plan is all set. But when are we actually going to start seeing these chemicals, you know, on the move through this conflict zone?

BOWMAN: Well, all the chemicals - that 500 tons - are supposed to be at that Syrian port by the end of the month, so just about two weeks. And supposedly they have already begun moving the chemicals, but we don't have a sense yet whether any of the chemicals have actually reached the port.

Now, the main problem, of course, is security - of course we're in the middle of a civil war. And one of the main roads that was contested is now under Syrian government control, so that's good news. And, of course, Syria has a responsible to move all of this chemical stockpile.

Another good peace of news in this effort is the Russian leaders said just yesterday they would help move the chemicals to the port. But they also said the same thing back in September. So we have to wait and see. But the sense is, the bottom-line is, with all these troubles with the civil war, that December 31st date might not be met.

GREENE: Okay. So just so we're clear, the end of the year deadline is to get the chemicals to the port. What happens then once these chemicals are transported by ship to this American vessel?

BOWMAN: Well, once these chemicals get on the American vessels, that ship would head out to sea and begin neutralizing the chemicals. And it's done by this hydrolysis system. They have two of these systems on board. And picture the kind of a big stainless steel vat you would see at a brew pub when you look through the glass. And the non-scientific explanation is you put the chemicals in, you add hot water, and basically bleach and other chemicals. And that neutralizes these dangerous chemicals and the byproduct. And you just simply go to a commercial waste repository.

GREENE: And briefly, Tom, once these chemical are neutralized, I mean is that it? Will Syria have complied with the deal that it struck?

BOWMAN: Well, removing these chemicals is very important, that's key. They're critical to their program. But the question is, you know, has the Syrians turned over everything. Syria has a pretty bad track record of cheating and noncompliance and the government has denied ever using chemical weapons. So some will say this might not be the end of this story.